The present invention relates to a method and system for treating atrial flutter.
Atrial flutter is a common rhythm disturbance defined as an atrial tachycardia with atrial rates exceeding 240 beats per minute.
Most methods of treating atrial flutter involve pacing the heart using an appropriate pacing rate.
Use of pacing pulses delivered at multiple sites within the atria to prevent the occurrence of atrial tachyarrhythmias including atrial flutter which may in some cases progress to atrial fibrillation, has also been investigated. For example, the article xe2x80x9cPrevention of Atrial Tachyarrhythmias related to Advanced Interatrial I Block by Permanent Atrial Resynchronisationxe2x80x9d by Daubert et al, Pace Vol. 14, P.648, 1991, discloses the use of synchronised pacing pulses delivered to the right and left atria to prevent onset of atrial tachyarrhythmias.
Whilst appropriate pacing, using an implantable pacemaker, is suitable for treating a wide range of arrhythmias, it is not appropriate for all patients and a permanent solution for preventing atrial flutter has been sought.
WO 96/34646 to Cosio et al proposes a catheter and method for treating atrial flutter using ablation.
The action of the heart depends upon electrical signals carried along the surface of the heart tissue. Sometimes these electrical signals become faulty. It has been found that ablating or burning the cardiac conduction pathways in the region of the problem destroys the tissue to eliminate the faulty signal. Electrophysiology catheters are known for ablating certain tissue using, typically, radio frequency (RF) energy directed to one or more high energy capable ablation electrodes.
The catheter proposed by Cosio is specifically adapted for treating atrial flutter.
The ablation catheter proposed by Cosio creates a linear lesion oriented perpendicular to the isthmus of tissue between the inferior aspect of the tricuspid valve and the inferior vena cava. The invention ablates a line of tissue across the critical isthmus using ablation-capable electrodes positioned along the tip of the catheter. The catheter is designed to remain in place and provide firm electrode contact during the ablation, despite respiratory, cardiac or blood motion during ablation.
The Cosio catheter has a dual curve configuration to conform to the anatomy of the heart.
The present invention aims to allow the treatment of atrial flutter by ablation to be speeded up without giving rise to any safety problems. Speeding up the procedure results in less x-ray exposure.
According to one aspect of the present invention there is provided a method of treating atrial flutter by ablation of cardiac tissue comprising inserting an ablation lead into the heart and fixing the lead tip by screwing such that electrodes arranged on the lead overlie the area between the tricuspid annulus and the inferior vena cava; applying radiofrequency energy to that area via the electrodes to cause ablation of the tissue; manipulating the lead with the tip screwed in position such that radiofrequency energy can be applied to the area between the coronary sinus and the tricuspid annulus to cause ablation of tissue in that area.
According to a second aspect, there is provided an ablation lead for treating atrial flutter, said lead comprising a lead body; a distal tip adapted to be fixed in position in the heart; and an array of electrodes for delivering RF energy; said electrodes being arranged on the lead body such that in use the electrodes can ablate the area between the tricuspid annulus and the inferior vena cava and also the area between the coronary sinus and the tricuspid annulus without displacing the tip; and wherein the lead tip is a screw tip.
The tip is preferably adapted to be fixed in the right ventricle. The screw tip is preferably of the Bisping type without an electrode.
The preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings.